The ability of nuclear magnetic resonance spectroscopy to monitor adriamycin (ADR)-induced cardiotoxicity will be studied. Initial studies will be performed on the Langendorff perfused rat heart model using 31P NMR to monitor changes in phosphorus metabolism as a result of ADR exposure. 1H NMR techniques will also be employed to evaluate the potential utility of NMR imaging as a diagnostic tool to monitor drug-induced cardiomyopathy. Spectral perturbations will be correlated with changes in heart functions, morphological changes and changes in the biochemistry and metabolism of the heart. To help evaluate the NMR technique as an indicator of chronic toxicity, studies will be performed on animals with surgically implanted coils; in addition, NMR imaging will be used on rats and rabbits without need for the implants. The NMR method(s) will be "calibrated" using drugs known to be cardiotoxic and then used to assess the predictive ability of the method on previously untested drugs. Chemicals will also be screened using this methodology for their ability to prevent cardiac toxicity. It is hoped that some of the biochemical processes involved in the expression of cardiomyopathy will also be delineated.